Having a nightmare with a 2 way switch!

28 Jan 2009
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United Kingdom
I have the house jack built.

I have tried the simple task of replacing switches on a lighting circuit. I have tried to sort out a faulty 2 way switch.
I firstly swapped the switches making sure all connections were like for like. I have a ground floor switch operating a landing light. This connects with a double switch for the bathroom and landing on the 1st floor.

The bathroom light works upstairs, the landing light works from downstairs but I can't get the landing light to work from the upstairs switch.

The downstairs switch is a standard two way switch. It has 4 core, earth Red Yellow and Blue.

Yellow(Y1) is Common, Blue(B1) is L/2 and Red(R1) L/1

On the double switch the bathroom switch had Y1 in L/1 with a Red wire(R2) going into a new feed(believe this is bathroom supply), the Black related to this supply was at L/2 on the bathroom switch as was the Blue (B1) from the hall feed.

The Red wire(R1) from the hall switch was connected to the common terminal on the landing switch. Also on this switch was another feed(believe this to be landing light supply), with the red wire (R3) at L/1 and the black wire(B3) on the common terminal of the bathroom light switch.

does this make any sense to anyone.
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Sounds like you've got your bathroom and your landing switch confused upstairs.

As I understand it, at the upstairs switch you have 3 cables, one 3C+E which goes to the downstairs switch, and two 2C+Es. One of these is probably the bathroom switch, so that should be wired to Com+L1 of the switch you want for the bathroom, job done. The other, is probably the switch for the landing light, which should be wired to L1 and L2 of the switch you want to use for the landing. Then wire the 3C+E in to the same terminals it's in downstairs, i.e. Y to Com, B to L2, and R to L1.

Note this is partly guesswork based on what you've described, but it would make sense - it's exactly what's on the wiki here: //www.diynot.com/wiki/electrics:lighting:two_way_lighting:chocknonharm
top draw!

for the very first time we have a fully functional 2 way switch.

The builder who installed it have been having an off day.


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